You are not using a standards compliant browser. Because of this you may notice minor glitches in the rendering of this page. Please upgrade to a compliant browser for optimal viewing:
FirefoxInternet Explorer 7Safari (Mac and PC)

Press Release

Voracious comb jellyfish 'invisible' to prey

Tuesday, October 12, 2010

The North American comb jellyfish Mnemiopsis leidyi has a simple structure with two large oral lobes for catching prey. Credit: Lars Johan Hansson

Despite its primitive structure, the North American comb jellyfish can sneak up on its prey like a high-tech stealth submarine, making it a successful predator. Researchers, including one from the University of Gothenburg, have now been able to show how the jellyfish makes itself hydrodynamically 'invisible'.

The North American comb jellyfish Mnemiopsis leidyi has long been known to consume vast quantities of zooplankton. A few years ago the species became established in Northern Europe.

Like many other jellyfish, Mnemiopsis leidyi has a large gelatinous body. The large size increases its chances of encountering prey, but can also be a disadvantage since the prey organisms are often highly sensitive to movements in the water. Nevertheless, the comb jellyfish manages to catch large amounts of copepod plankton, which are known for their acute escape response.

Able to catch the world's most vigilant plankton

'Copepods have a well developed ability to detect even the slightest water disturbance,' says Lars Johan Hansson, a researcher at the Department of Marine Ecology at the University of Gothenburg. 'They can swim well clear of the source of water deformation in just a split second. How the comb jellyfish is able to approach and catch some of the animal world's most vigilant plankton has up until now been unknown.'

The researchers used advanced video technology to study water flows around and within the comb jellyfish. These measurements were then used to calculate the water deformation generated by the jellyfish and compare this with the levels that trigger an escape response in copepods.

'It emerged that the comb jellyfish uses microscopic, hairlike cilia inside its oral lobes to generate a feeding current that carefully transports water between the lobes. As the water accelerates slowly and is transported undisturbed into the jellyfish together with the prey, there is nothing that alarms the prey until it is next to the capture site inside the lobes, by which time it's too late to escape. This makes the jellyfish a hydrodynamically silent predator.'

This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.

Results of largest ever genetics study of a single population could also help refine dates for major events during human evolution Humans are evolving more rapidly than previously thought, according to the largest ever genetics study of a single population.

Latest genetic tests reveal another break in the male line, potentially undermining the legitimacy of the entire House of Plantagenet When scientists revealed last year that an adulterous affair had apparently broken the male line in Richard III’s family tree, they vowed to investigate further.

A leading researcher issues a call for pills that deliver a full course of treatment in one swallow.One of the world’s preëminent biomedical researchers is calling for a concerted effort by scientists to develop pills that would stay in the stomach or gut for weeks or months once swallowed, delivering one or more drugs continuously or over set intervals.